title: Claulansine F promotes neuritogenesis in PC12 cells via the ERK signaling pathway.
abstract: OBJECTIVE
  To study the effects of Claulansine F (Clau F), a carbazole alkaloid isolated from the stem of Clausena lansium (Lour) Skeels, on neuritogenesis of PC12 cells, and to elucidate the mechanism of action.
  
  
  METHODS
  Neuritogenesis of PC12 cells was quantified under an inverted microscope. Expression of the neurite outgrowth marker GAP-43 was detected using immunofluorescence. GAP-43 transcription was measured using RT-PCR. Cell viability was evaluated with MTT assay. The levels of phosphor-ERK1/2, phosphor-CREB, phosphor-AKT and acetylate-p53 in the cells were examined using Western blotting analyses.
  
  
  RESULTS
  Clau F (10-100 μmol/L) significantly increased the percentage of PC12 cells bearing neurites. Clau F markedly increased the expression of GAP-43 in the cells. The efficiency of Clau F (10 μmol/L) in increasing neuritogenesis and GAP-43 expression was comparable to that of nerve growth factor (50 ng/mL). In addition, Clau F completely blocked the proliferation of PC12 cells within 7 d of incubation, whereas it did not cause cell death in cultured rat cortical neurons. Treatment of PC12 cells with Clau F activated both ERK and AKT signaling pathways. Co-treatment of PC12 cells with the specific ERK inhibitor PD98059, but not the specific PI3K inhibitor LY294002, blocked Clau F-induced neuritogenesis and GAP-43 upregulation.
  
  
  CONCLUSIONS
  Clau F promotes neuritogenesis in PC12 cells specifically via activation of the ERK signaling pathway.
authors.affiliation: 1] State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Beijing Key Laboratory of New Drug Mechanisms and Pharmacological Evaluation Study, Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China [2] Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China.
authors.forename: Yin-zhong
authors.initials: YZ
authors.lastname: Ma
authors.forename: Na
authors.initials: N
authors.lastname: Ning
authors.forename: Wen-bin
authors.initials: WB
authors.lastname: He
authors.forename: Jing-wei
authors.initials: JW
authors.lastname: Li
authors.forename: Jin-feng
authors.initials: JF
authors.lastname: Hu
authors.forename: Shi-feng
authors.initials: SF
authors.lastname: Chu
authors.forename: Nai-hong
authors.initials: NH
authors.lastname: Chen
mesh_terms: D000818:Animals; D002227:Carbazoles / Q000494:pharmacology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D016501:Neurites / Q000187:drug effects* / Q000502:physiology; D016716:PC12 Cells; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D002227:Carbazoles; C000588613:claulansine F; D048049:Extracellular Signal-Regulated MAP Kinases